Improvement in annealing sheet iron



W. D. WOOD. ANNBALING SHEET IRON.

No. 66,546` Patented July 9,1186?.

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Y Letters Patent No. 66,546, dated JulyY 9, 1867.

IMPROVEMENT IN ANNELING SHEET IRON.

To ALL wHoM IT MAY coNoERN:

Be it known that I, W. DEWEES WOOD, of the borough of McKeesport, in the county oi" Allegheny, and State of Pennsylvania, have invented a new and useful Improvement in the Process of Annealing Sheetlron; and I do hereby declare the following to be a full, clearfand exact descriptiontlereof, reference being had to the accompanying drawing, forming part of this specitication1in which- Figure 1 is a perspective representation of my improved annealing-box.

Figure 2 is a transverse vertical section.

In both figures like letters of reference denote similar parts.

Sheets of iron and other metals are annealed by placing them in piles-within a heavy cast-iron box, from which the external air is excluded. by closing the joints with sand, and placing the box with its contents in a furnace, in which it is'exposed to a high hen-t, and then afterwards gradually cooled. These cast-iron annealiugf boxes are necessarily made very heavy, in order that they may preserve their shape when exposed to the heat of the annealing furnace, because, when they become warped and misshapen, they are useless, as it is then impossible to close them so as to exclude the air. They are usually made to weigh about four tons, andare very expensive, but notwithstanding their heaviness, they last only a short time before they become so twisted and warped as to be nolonger t'foruse. Another practical difficulty in the use ofl annealing-boxes for sheet iron is that the sheets of metal become discolored at their edges, the' discoloration being owing to the eect of the air whichV surrounds the pile of Vsheets in the'box, and which is contained irrthe box when it is closed up. These diiculties, v iz, the warping of the annealing-box and the discoloration of the sheets duringl the annealing process, I propose to remedy in a great degree by my improvement, which consists in compressing together the sheets of iron or other metal within the annealing-box between the parallel surfaces of its bottom and cover, and screwing, or otherwise forcibly holdingr together, the top and bottom pieces 'of the box, so as not onlyto prevent the Vwarping of the box, but also prevent the entrance of air between the layers.

To enable others skilled in the art to construct and use my improved annealingbox, I will proceed to describe its construction and the manner in which it is to be used.

Inthe accompanying drawing a is the bottom piece or bed-plate ofthe annealing-box, consisting of a plate of cast iron, rectangularin shape, with a plane surface on the upper side and a raised ledge or rim b around its edge, on all four sides, for the purpose of retaining the-sand packed around the box to exclude the air. The under side of the bed-plate a is furnished with boxes e for the receptionrof flanged. truck-wheels d, so placed that the box may he run in and out of the anncaling-furnace on a rail track, e e. l The upperl piece or boxf consists of four sides and a top, cast in one piece. It is strengthened by a rib, g, extending along eaph side from end to end, and the top of the box extends beyond the sides all round, so as to form a ledge, 7i, projecting as far as the outer edge of the bottom piece a. The upper piecefthus forms a b'ox having a rectangular cavity, which is pla-ced with the open bottom downwards on the bottom piece or bed-plate a, as shown in g. 2, the sides of the box being inside the raised rim b, and not quite l'touching it, so as t'o allow sand to be packed between the rim l and the sides of the boxf. The box piecefis fastened to the bed-plate a by means of clamps c placed at suitable intervals on each side and at both ends. The clamps 7s have a T head, z', at one end, and a tapering recess or mortise near the other end, to receive a. wedge-shaped key, n.v Thess clamps are placed ver tically on the sides of thebox, and are let into suitable recesses4 m m in the rim of the lbed-plate a andin theledge of the box piccef, the T head resting-against the under side of therim of the bed-plate a. Near each of the four corners'of the box, in the ledge L of the box, is a round hole, zu, to receive `the end of a screw-bolt,p, which has a T head at the other end, the bolt entering a recess, g, iu the rim of the bed-plate, andthe T head restingv against the under side of the rim of the bed-plate. The upper end of these bolts p is chased with screwthreads, and a nut, r, screwed on the bolt, serves to force down the boxf on the bed-plate a, and press together thc sheets of iron placed in thc'box between its cover and the bed-plate a.

The mode of using my improved annealing-box is as follows: The box pe'cef, being hoisted by a'crane or otherwise from the bed-plate a, the sheets of metal to be annealed are placed one on top of another in layers` on the bedplate,' forming a pile so high that when compressed the bottom of the box piecef-shall not lquits touch the surface of the bod-plate a. The box is then placed over the pile ofv sheets, land the screw-boltsp are Ainserted at the four corners of the box, and the nuts r screwed down until the sheets are compactly pressed together. If preferred,this may be done by an hydraulic or other press instead of by screw-bolts. While the box fis thus pressed down on to the sheets of metal, the clamps 7c are inserted into their respective grooves or i recesses, and the keys n are -driven into their mortises, so as to hold the boxffirmly down toits place. The screwboltsp are then removed, as the heat of the annea-ling furnace would injure them, and the box is ready to be run into the furnace. The mode of fastening together the box and bed-plate, which I have described, Iconsider most convenient, although others'may be used, such as clamps surrounding or partially surrounding the box. When thus rigidly connected together and allowed to cool before the clamps are removed, the box piece and bed-plate retain their shape, and can be used repeatedly for along time. The efect produced `by th-us rigidly compressing together the sheets of iron during the process of annealing is greatly to improve their appearance and iinish.

This is especially important in the manufact-ure of glazed or polished sheet iron, (known as imitation Russia,)

Whereso much depends on uniformity of color. In the ordinary Inode of annealing, although the sheets are pressed'down merely by the weight of the annealing-box, yet the air within the box iindsA its way between the layers of metal, and produces considerable discoloration; but' by my method of rigidly compressing the sheets together th-eyare brought so closelyin contact with each other that the air can only penetrate a very slight distance at the edges, so that the sheets are o t' uniform color and finish, excepting `just at their margin. This compression of the sheets, as distinguished from mere pressure by superimposed weight, may be also obtained by placing them between plates screwed together to form a solid pack, whichis placed in an annealing-box; but this is not se desirable, as it leaves mere air space around the iron in the-box, and the screw-together of the box, as before described, accomplishes the desired result, whilst it also preserves the box from warping.

that I claim as my invention, and desire to secure by Letters Patent, is-

1. The use, in the process of annealing sheet iron, of boxes so constructed, substantially as hereinbefore described, as that vthe sheets may be compressed between the top and bottom of the box, for the pur'poseof prel venting their discoloration.

2. The use of annealing-boxes, so constructed as that the box piece and bottom piecepmay be clamped or securely fastened together, for the purpose of preserving the shape of the'box and preventing its warping while cooling, substantially as hereinbe'fore described.

3. Annealing imitation Russia or other glazed or .polished sheet iron, in packs or layers, forcibly compressed together, and held under rigid compression during the process of annealing.

In testimony whereof I, the said W. DEWEES WOOD, have hereunto set my hand in presence of- W. DEWEES WOOD.`

Witnesses:

ALLAN C. BAKEWELL, W. BAKEWELL. 

